This disclosure relates in general to an electrophotographic system, and more particularly, to the controlling of wrinkling of printed pages in belt roll fuser.
Generally, in a commercial electrostatographic reproduction apparatus (such as copier/duplicators, printers or the like), a latent image charge pattern is formed on a uniformly charged photoconductive or dielectric member. Pigmented marking particles (toner) are attracted to the latent image charge pattern to develop such image on the dielectric member. A receiver member, such as paper, is then brought into contact with the dielectric member and an electric field applied to transfer the marking particle developed image to the receiver member from the dielectric member. After transfer, the receiver member bearing the transferred image is transported away from the dielectric member and the image is fixed or fused to the receiver member by heat and/or pressure to form a permanent reproduction thereon. In a typical fusing process where the toner is fused to the paper or receiving member, two rolls are used through which the paper travels during the toner fusing. One roll, usually the harder roll, is a fuser roll, the second roll is the pressure roll or the softer roll.
Typical pressure rolls (“Softer Roll”) that are used in a fusing system have an elastomeric coating like silicone rubber which may or may not have a thin layer of another material over the surface of the roll. A functional nip is formed when the softer roll is pressed into the fuser roll (“Harder Roll”). The fuser roll generally comprises a metal core with a hard coating or thin elastomer.
In any system when a hard roll (fuser roll) is pressed against and contacts a softer roll nips are formed throughout the length of the pressure roll in contact with the fuser roll. These pressure zones ultimately cause the softer material to contact the support plates and create wear, shortening roll life and causing debris in the system. Also, once excessive wear takes place and an uneven nip is formed, improper fusing of the toner can result causing imperfect copies on the paper or receiving member. Also, a non-uniform nip causes uneven contact with the paper, uneven fusing of the toner, paper wrinkles and excessive rubbing against a support plate causes the roll to wear and create debris in the system.